XM Magdalena 3D print, GGeorgy (3D)
LC #42 Pipers Alley

View Full Version : displacement maps in mental ray

06-24-2010, 09:30 PM

I'm having problems using mental ray to render displacement maps applied to polys. The displacement maps are attached to grayscale .jpg files that I am creating in PS.

Is there a step that I'm missing to get them to render in mental ray and not just in software?

Thank you for your help!

06-24-2010, 09:48 PM
i don't know if u know that or not ... select the mesh
windows>rendering editor>mental ray > approximation editor > create for poly
filter spatial min 4 max 5 length 0.01 or higher
for the disp file > color balance > alpha gain 1 = alpha offset -0.5
that may help
if the result is over reduce or increase alpha g and offset

06-28-2010, 02:06 PM
can you post an image of your render

06-30-2010, 02:02 PM
here are stills of my render... http://christo.irc.umbc.edu:16080/nasa/meganNasa/cgforum/testrender_displacement1.jpg , http://christo.irc.umbc.edu:16080/nasa/meganNasa/cgforum/testrender_displacement2.jpg , http://christo.irc.umbc.edu:16080/nasa/meganNasa/cgforum/testrender_displacement3.jpg , http://christo.irc.umbc.edu:16080/nasa/meganNasa/cgforum/testrender_displacement4.jpg . i did use the approximation editor but i still feel like the ground could look higher-res? i used subdivisions bc the displacement tesselation wasn't looking right. any suggestions would be greatly appreciated!

07-02-2010, 07:26 AM
You cannot use the jpeg format for displacement maps, and in fact shouldn't even use jpegs as at all because they are a lossy compression format. Without getting too technical, a jpeg can't hold enough value range (8 bit) to use for displacement. You need to use a 16 bit format like TIF, or ideally a 32 bit format like an EXR.

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07-02-2010, 07:26 AM
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